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SEMINARI: My quest for Ice-Age Equator 40 years after Paul Colinvaux’s Amazon expeditions

Seminari_IBB_27102015Cicle de seminaris IBB

Títol complet: My quest for Ice-Age Equator 40 years after Paul Colinvaux’s Amazon expeditions: Long-term dynamics of a mega-diverse ecosystem in central Ecuador

Ponent: Encarni Montoya, investigadora del’Institut de Ciències de la Terra Jaume Almera (ICTJA-CSIC)

Data: Dimarts 27 d’octubre de 2015, 12:00 hores

Lloc: Sala Salvador de l’IBB


RESUM

Trends in biodiversity are especially difficult to assess in the Neotropics given the magnitude of: i) number of taxa, ii) complex multi-level trophic interactions, and iii) spatial and temporal scales embraced. Regarding temporal scale, current tropical ecosystems are known to be highly dynamics, as well as being the result of long-term (> centuries) processes. On the other hand, the long-term study of Neotropical ecosystems is very limited based on the paucity of long and continuous Late Quaternary records. In this sense, pioneer Dr Paul Colinvaux started his research in the Neotropics during the 60’s, developing the first steps for Neotropical palaeoecology. Among his main interests was to study tropical vegetation during glacial times and their responses to climatic changes. After several decades of field research, he only found one open section (road outcrop) that has been highly debated by the scientific community. Here, we present the palaeoecological study of Lake Pindo (1250 m asl; central Ecuador), spanning the last 50,000 years, through a multi-proxy approach based mainly on pollen, and supported by charcoal, non-pollen palynomorphs (NPP), chironomids, and stable isotopes analyses. Full glacial interval of Lake Pindo was characterised by a relatively stable plant community, formed by taxa nowadays common at both mid and high elevations, and the almost absence of other biological proxies. Mid-Holocene section was marked by a replacement of high by mid elevation plant taxa, resulted in no major changes in taxa richness but an increase in ?-diversity (traits). Fungal spores started to be a common feature during this interval. Finally, the last 3000 years of Lake Pindo were characterised by a dramatic increase in both plant taxa richness and diversity, also observed in other proxies such as NPP and chironomids. Besides being a forest (Melastomataceae-dominated) during the last 50,000 years, Lake Pindo record shows that taxa were mostly different for each interval, and showed during the most recent period rapid dynamics, with replacements of dominant taxa occurring in decadal scales, where anthropogenic and volcanic activities occurred.

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